renal sac的用法和樣例：
例句
- Here is a much larger simple renal cyst of the upper pole.
腎臟上極更大的單純性腎囊腫，還有一些小囊腫散佈於腎臟。 - Conclusions Typical cystic renal carcinomas can be well diagnosed, while atypical cases may be misdiagnosed in benign renal cysts by ultrasonography.
結論超聲能對典型囊性腎癌作出正確診斷，但不典型者可誤診為良性腎囊腫。
